1. The Coulter Principle
For Ink Toners
Kira Shapiro
Particle Characterization Group
508-479-3780
kbshapiro@beckman.com

2. Technique Comparison
Laser Coulter Principle Nanoparticle Pore Analysis
Diffraction Analysis
Size Range 17 nm– 2 mm 400 nm – 1.7 mm 0.6 nm – 7 um 3 nm -200 nm
(pore diameter)
Resolution Medium Very High Low Medium
Sample Medium Small Small Small
Volume
Primary Broad Concentration and Size and Zeta Pore Size
Applicatio Distributions Size Potential Distribution
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Our LSTM Series MultisizerTM DelsaNanoTM SA3100TM
Solution Series

3. Coulter Principle
• Each particle is measured individually
• Results are not affected by particle color, shape,
composition or refractive index.
• Based on electrical impedance
• Only technology to allow COUNT and SIZE

4. Coulter Principle
Aperture Size
(μm) Range
20 0.4 – 12
30 0.6 – 18
50 1.0 – 30 Dynamic Range:
1:30 in diameter,
70 1.4 – 42 1:27,000 in volume
100 2.0 – 60
140 2.8 – 64
200 4.0 – 120
280 5.6 – 128
400 8.0 – 240
560 11.2 – 336
1000 20 – 600
2000 40 - 1200

5. Applications: Ink Toners
• Particle size determines ink
characteristics
• Reference methods:
– ASTM F751-83
– ASTM F577-83
• Major Global Application
Toner size affects how well inks bind to paper, how fast they dry,
printer handling requirements, etc.
The Coulter Principle is the #1 technique for monitoring ink
toners.
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6. Applications: Ink Toners
Size distribution is critical for the manufacturing process

7. Applications: Toner Industry
Toners have a tendency to agglomerate.
The Size Distribution graph does not make possible to detect
when agglomeration takes place during sample analysis.

8. The Pulse Distribution graph makes possible to detect when
agglomeration takes place during sample analysis.

9. Applications: Toner Industry
Controlling the Quality of Toners

10. ASTM Test Methods
• Test Method F751-83 (1997) Standard Test
Method for Measuring Particle Size of Wide-
Size Range Dry Toners.
• Test Method F577-83 (1997) Standard Test
Method for Particle Size Measurement of Dry
Toners